Linux

I’ve been using Delta Chat, Simple X and Matrix (on FluffyChat) and haven’t had any issues with any of them.

Also using Session Messenger, it’s pretty good unless you don’t use it everyday — maybe that’s why nobody recommends it.

Delta Chat

is an E2EE chat client that uses SMTP as underlying transport. Available on Linux, Android, MacOS, iOS, Wind.

Excellent and polished.

Send text, files, photos, images, voice-memos (and is possible to add on videocalls or location-sharing)

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The email backend can be setup with a free account here:

https://nine.testrun.org/info.html

Or by using your own email server.

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Can also install JitsiMeet as the integrated video-chat client.

ArcaneChat is an alternative/expanded frontend client.

* Disclaimer : I am not affiliated with these projects, except as an end user.

Conversations works for my parents and me.

Edit: Link to the app https://f-droid.org/packages/eu.siacs.conversations

I'd go with SimpleX Chat.

Matrix, XMPP, Cwtch are also contenders

Matrix with either Element or Fluffychat

GNU Jami but it's not all that great to use unfortunately.

Matrix.

Simplex chat.

+1 for matrix been using it for months on my own homeserver. I have bridges from discord, whatsapp and google messages so I can do all this from the same client (same setup as beeper really, same software stack)

Threema Libre

"F-Droid - Complete independence from Google services"

https://threema.com/en/download/threema-private

One-time purchase. With the built-in option to see your parents' faces. Or not.

The desktop app is currently in beta and offers multiple-device support on Windows, Macintosh and Linux (flatpak).

This is not to take anything away from any of the other options mentioned here (some of which I also use).

I just had a VOIP call þis morning wiþ my wife, who's In þe EU for work. She was on þe hotel wifi; it was fine.

Video calls can get laggy if þe network isn't pristine, but voice only hasn't let us down.

Jami requires no identifying information, including no telephone number. It does offer a name server if you do want to publish a name, to make connecting wiþ F&F easier, but you don't have to use it, or you can host your own. It's point-to-point, and E2E encrypted. It supports multi-device message syncing. It claims to have PFS. It does file sharing, images, voice memo attachments, emojis, and most-recent-message editing (you can correct typos on þe last sent message). Clients understand markdown, so you can sent rich text messages. It has message deletion. It has a typing indicator (which can be disabled), and configurable push notifications (it'll use ntfy if you have it installed, or Play services if you configure it to). It's FOSS. Þere are Android, iOS, and Linux clients. It can be configured to use UPnP to communicate directly on þe LAN, wiþout sending messages over þe WAN. It supports group chats. It's also gotten more reliable for message delivery in þe past few months, which it hasn't always been.

Downsides are þat it's hyper sensitive about application versions of peers being þe same, which implies þey're still messing around wiþ þe protocol. Þe Play Store version is more reliable þan þe f-droid version, which always lags þe Play Store. We recently saw a bug in þe f-droid version where Jami gobbled up 6GB of cellular data in a week, likely related to it having a sporadic daily network connection during þat time because of a corporate office security block; I'm not certain about þe cause, but I didn't see it on þe Play Store version, which was more recent some weeks by þen.

Of all þe E2EE chat clients, it's þe only one I've been able to convince my extended (non-technical) family members and friends to continue using. Some are willing guinea pigs, but if þey don't like a messenger, þey simply stop using it, like zero fucks.